The present invention relates generally to dispenser assemblies for receptacles such as fragrance or personal care bottles, and in particular, to an improved collar for use therewith that significantly reduces the likelihood that the dispenser assembly will inadvertently or undesirably become decoupled from the receptacle, without sacrificing the ease of which the collar can be initially positioned thereon. That is, the present invention is directed to an improved dispenser assembly that maximizes the “off-to-on” force of application and removal forces for the collar. An improved method of assembling the dispensing assembly on the receptacle is also provided.
Generally speaking, prior art fragrance and personal care pumps consist of a pump module, a manual actuator for operating the pump, a ferrule that contains the module and crimps onto the receptacle (i.e. glass or plastic container), a gasket that seals the ferrule to the top of the receptacle's neck and a decorative collar. A cap may also be provided over the collar either in a slip-fit or a snap-fit arrangement.
Typically, the pump is retained on the bottle by one of two methods:
(a) the lower edge of the ferrule, typically comprised of aluminum, is collapsed inwardly under the neck of the receptacle by a crimping tool. After mounting, the collar is pushed over the ferrule as a separate operation; or
(b) a ferrule, made of either plastic or metal, has its multiple legs folded under the neck of the receptacle by sliding the collar down the ferrule. The collar is partially preassembled to the ferrule at the pump manufacturer's plant and the assembly is then mounted on the bottle at the customer's plant in one operation.
In either case, the collar can be metal or plastic. Usually, retention of a plastic collar on the ferrule is not a major concern because designs incorporate snap fits or heavy press fits that do not compromise the outer aesthetics of the collar. However, metal collars are usually fabricated in aluminum and then anodized to produce a lustrous surface. In order to accommodate physical tolerances in the ferrule and collar diameters, the internal surface of the collar may contain multiple elongated vertical ribs (see FIGS. 1 and 1A) that project outwardly several thousandths of an inch off the inner surface thereof. When the collar is pushed over the ferrule with a heavy press fit, the collar slightly distorts, or “breathes,” into a polygon, giving it a resiliency that deals with the tolerances. Another attribute of the ribs is to concentrate the “hoop” stress at multiple points, causing the ribs to dig into the ferrule and thus increasing the resistance to removal.
However, finding the optimal parameters that provide the best seal of the pump to the receptacle is difficult and heretofore has been elusive. For example, although the press fit over the ferrule must be large enough to assure that the collar cannot be accidentally pulled off the ferrule, it must be low enough to avoid damaging the outer surface of the collar. That is, the anodized surface of the collar is typically a very thin film of aluminum oxide that contains a colorant dye. When stressed in tension, the oxide film can crack, creating a diffraction grating that produces a rainbow effect, which detracts from the aesthetics. As a result, the rib locations become evident on the outer surface of the collar, a condition known as “crazing”.
Similarly, while the press fit must be high enough to compress the gasket sufficiently to assure a seal to the bottle neck so as to avoid leaking, the press fit should not be so high as to over-compress the gasket, causing it to extrude out from under the ferrule, or creating such large forces that the bottle collapses or breaks.
Accordingly, it can be seen that improvements in the art are still desired. Specifically, it is desired to improve the state of the art collars to be able to increase the needed force to remove the collars while simultaneously not requiring so much force in initially applying the collar that crazing, bottle leaking or breaking occurs.
One such proposal that has been suggested is to provide spiraling ribs in the inner surface of the collar. One exemplary construction that appears to utilize spiral ribs is described in U.S. Pat. No. 5,799,810. However, it is believed that the descriptions and the resultant product therein are less than satisfactory and that still further improvements are achievable. Specifically, it is believed that the spiral ribs in this '810 patent are not provided to hold the collar on, but rather, to permit the collar to be unsecured after the contents of the receptacle have been used up, all for the purpose of recycling. Moreover, the '810 patent's inherent description of restricting any rotation of the collar as it is being fitted over the ferrule provides for less than satisfactory results. That is, and as further discussed below, the severe angle of the ribs in this prior art patent prevents rotation of the collar as it is being fitted on the ferrule, resulting in more of a “snowplow” type deformation of the plastic ferrule, and a less than satisfactory “off to on” ratio for the collar.
Accordingly, it is desirable to provide an improved dispensing assembly that further advances the state of the art. In particular the present invention seeks to reduce the required application force so as to avoid collar crazing while simultaneously providing for (a) sufficient gasket compression without extrusion, (b) a desirable amount of required removal force, and (c) an increase in the ratio of axial collar removal force to application force. The present invention achieves these as well as the below mentioned objectives.